Solid-state self-emission display and its production method

ABSTRACT

The present invention provides a solid state light-emissive display apparatus of high brightness and efficiency, high reliability, and of thin type, and method of manufacturing the same at low cost.  
     Said apparatus has the luminous thin film made up by laminating or mixing crystal fine particle coated with insulator ( 5 ) of nm size and fluorescent fine particles ( 7 ) of nm size, and the lower electrode and the transparent upper electrode sandwiching said luminous thin film, wherein the electrons injected from said lower electrode are accelerated in the crystal fine particle coated with insulator layer ( 6 ) not being scattered by phonons to become high energy ballistic electrons, and form excitons ( 13 ) by colliding excitation of fluorescent fine particles. Since said fluorescent fine particles are of nm size, the exciton concentration is high, and luminescence intensity by extinction of excitons is also high.

TECHNICAL FIELD

[0001] The present invention relates to solid state light-emissivedisplay apparatus utilizing a quantum size effect and method ofmanufacturing the same.

BACKGROUND ART

[0002] The display apparatuses using liquid crystals are lately in widespread use, but these are not the best in such properties asenergy-saving or brightness, since a liquid crystal display apparatususes backlight in principle. For this reason, the research anddevelopment are widely proceeding for a solid state light-emissivedisplay apparatus, aiming to realize high brightness, energy-saving,flat type, and high reliability rather more than liquid crystal.

[0003] As an existing solid state light-emissive display apparatus,there is EL(Electro Luminescence) display apparatus. EL displayapparatus is composed of pixels each of which has a semiconductor layerincluding light emission center atoms and insulator layers sandwichingsaid semiconductor layer. As a light emission center atom, such elementsthat emit visible fluorescence, for example, Mn or rare earth elementsare used, and as a semiconductor layer, such semiconductors that havelarger band gap energy than visible light, for example, ZnS or else areused, and as insulator layers, such insulators that have a propertywhich prevents dielectric breakdown of said semiconductor layers, forexample, thin films of SiO₂ or Si₃N₄ are used.

[0004] EL display apparatus emits light as following, electrons in asemiconductor are accelerated by high electric field imposed throughinsulation layers, the accelerated electrons collide to light emissioncenter atoms to be excited, and the excited light emission center atomsemit fluorescence light. Therefore it is the specific feature of ELdisplay apparatus that electric energy directly converts to lightenergy.

[0005] However, there are problems such that light emission efficiencyis low and dielectric breakdown tends to occur, because considerablyhigh electric field (10⁶ V/cm or higher) is necessary to accelerate theelectrons to such a high energy state (hot electron state) to emit ELlight against the energy dispersion by phonon scattering. There are alsosuch EL display apparatuses using organic materials as the semiconductorlayer, but they also have problems such that emission efficiency easilybecomes lower as organic materials are unstable and readily deteriorate.

[0006] There are also FED (Field Emission Device) display apparatuses asthe display apparatuses to generate fluorescence by colliding andexciting light emission center atoms by accelerated electron (ballisticelectron). However, an FED display apparatus has its problems such that,though it can emit light at relatively low electric field, it requiresvacuum space and hence it can not be made to a flat and all-solid statetype, since it emits out electrons into vacuum by using a field-emissiontype electron gun and accelerates them in vacuum.

DISCLOSURE OF THE INVENTION

[0007] Taking into consideration the afore-mentioned problems, theobject of the present invention is to provide a solid statelight-emissive display apparatus which has much superior properties toexisting display apparatuses in brightness, efficiency, reliability, anda thin type. And also the other object of the present invention is toprovide a method of manufacturing the said apparatus, which manufacturesit at low cost.

[0008] In order to achieve the object mentioned above, there is provideda solid state light-emissive display apparatus according to the presentinvention, characterized in that it has light emitting pixels comprisingof a luminous thin film composed of crystal fine particles ofnm(nanometer) size coated with insulator and fluorescent fine particlesof nm size in a form of laminating of two said each particle layers orin a form of mixed layer of said two particles, and a lower electrodeand a transparent upper electrode sandwiching said luminous thin film,whereby to obtain luminous display by impressing alternating voltage ordirect current voltage between said upper and lower electrodes.

[0009] In the solid state light-emissive display apparatus according tothe present invention, said crystal fine particle of nm size coated withinsulator is characterized in that it consists of a semiconductor or ametal single crystal fine particle of nm size and insulator film of nmthickness coated the surface of said single crystal fine particle.

[0010] In the solid state light-emissive display apparatus according tothe present invention, said crystal fine particle of nm is preferably aintrinsic or impurity doped Si single crystal fine particle of nm size,and said insulator film is a SiO₂ film of nm thickness coating thesurface of said Si single crystal fine particle.

[0011] Also preferably, said fluorescent fine particle of nm size is asemiconductor fine particle having a band gap energy corresponding to anenergy ranging from ultraviolet light to visible light. Said fluorescentfine particle of nm size may have a donor or/and an acceptor. Also saidfluorescent fine particle of nm size may be a semiconductor fineparticle involving luminous atoms or luminous atom ions.

[0012] According to the above mentioned makeup, the voltage impressedbetween the lower and the upper electrodes are distributed to theinsulator films coating the crystal fine particles of nm in the luminousthin film, the electrons injected from the lower electrode areaccelerated by the electric field distributed to the insulator film,passes through said insulator film by tunneling or resonant tunneling,and passes through the single crystal fine particle of nm size withoutbeing scattered by phonons (Refer to JP 2001-332168, for example). Theelectrons repeat the above mentioned process for each adjacent crystalfine particles of nm size coated with insulator as a result to obtainhigh kinetic energy, and collide the fluorescent fine particles of nmsize. If the kinetic energy of the colliding electron is higher than theband gap energy of the fluorescent fine particle, a free electron and ahole are generated in the fluorescent fine particle, and a free excitonis generated from these

[0013] free electron and hole.

[0014] Since the fluorescent fine particle is of nm size, said electronand hole are enclosed in space of nm size, the concentration of saidfree exciton is raised, and hence the luminous intensity by extinctionof said free excitons is increased.

[0015] Also, in case that the fluorescent fine particle has a donoror/and an acceptor, the generated electron and hole form a bound excitonvia a donor or/and an acceptor. Since the fluorescent fine particle isof nm size, the electron and the hole are enclosed in space of nm size,hence the concentration of bound exciton is raised, and the luminousintensity by extinction of said bound excitons is increased.

[0016] Also, in the case of fluorescent fine particle including luminousatoms or luminous atom ions, since the electrons having high kineticenergy are generated in large quantity by crystal fine particles coatedwith insulator, luminous atoms or luminous atom ions in fluorescent fineparticles are excited in large quantity, and luminous intensity isincreased.

[0017] Thus, according to the present invention, since electrons can beaccelerated without energy loss and exciton concentration can be high,the luminous efficiency and brightness are high. Also, since theluminous thin film is thin and can emit light by itself, the apparatusof this invention can be made extremely thin. Also, since the appliedvoltage is low, reliability is high.

[0018] And, the solid state light-emissive display apparatus accordingto the present invention is characterized in that the upper and thelower electrodes are configurated in a form of matrix configuration, andthe intersected region of the upper and the lower electrode are used asa light emitting pixel by simple matrix driven with these electrodes.

[0019] According to the makeup mentioned above, an image displayapparatus of high efficiency, high brightness, thin type, and highreliability can be provided.

[0020] Further, the solid state light-emissive display apparatus of thepresent invention is characterized in that wirings for scanning andwirings for signals are provided in a form of matrix electrodeconfiguration, a thin film transistor is provided at each intersectionsof said scanning and signal wirings, the gate electrode of said thinfilm transistor is connected to scanning wiring, the drain electrode ofsaid thin film transistor is connected to signal wiring, the sourceelectrode of said thin film transistor is connected to an electrode of alight emitting pixel, a luminous thin film is sandwiched by saidelectrode and upper electrode of said light emitting pixel, wherein eachlight emitting pixels can be actively driven by said each thin filmtransistors selected by said scanning and signal wirings.

[0021] According to the makeup mentioned above, since the opticaldistinction ratio between adjacent pixels can be made high, an imagedisplay apparatus of high efficiency, high brightness, thin type, andhigh reliability, and extremely high resolution can be provided.

[0022] Next, in order to achieve the other object mentioned above, thereis provided in accordance with the present invention a method ofmanufacturing the solid state light-emissive apparatus characterized inthat it comprises the steps of: forming Si single crystal fine particlesof nm size being floating in an atmosphere by pyrolyzing SiH₄ gas, andconveying said floating Si single crystal fine particles into O₂ gasatmosphere, whereby the surface of said Si single crystal fine particlesto be coated with SiO₂ film of nm thickness.

[0023] According to the makeup described above, since the Si singlecrystal fine particles are formed in a state of floating and SiO₂ filmis formed on the surface of said floating Si single crystal fineparticles in a state of floating, Si single crystal fine particles donot contact mutually not to be combined with each other, and hencemutually isolated Si single crystal fine particles coated with SiO₂ filmcan be provided.

[0024] By using above mentioned particles, a solid state light-emissiveapparatus can be manufactured by dissolving the crystal fine particlesof nm size coated with insulator and the fluorescent fine particles ofnm size into respective solvents, soaking a substrate and then taking itout in turn with respective solvents, whereby to laminate the layers ofthe crystal fine particle of nm size coated with insulator and thelayers of fluorescent fine particle of nm size.

[0025] According to the makeup above mentioned, a mono-layer whichconsists of the crystal fine particles coated with insulator beingdensely aggregated on the substrate, is obtained by one time processingof soaking a substrate into the solvent dissolving the crystal fineparticles of nm size coated with insulator and taking out there-from,and the desired thickness of the layer is obtained by repeating theabove processing. Then, a mono-layer which consists of the fluorescentfine particles of nm size being densely aligned on the layer of thecrystal fine particles of nm size coated with insulator on thesubstrate, is obtained by one time processing of soaking the substrateinto the solvent dissolving fluorescent fine particles of nm size andtaking out there-from, and the desired thickness of the layer isobtained by repeating the above processing. As the result,

[0026] the luminous thin film can be provided, in which the crystal fineparticle layer of the desired film thickness and the fluorescent fineparticle layer of the desired film thickness are laminated.

[0027] According to the above mentioned method, since those fineparticles can be densely packed with only a few gaps between those fineparticles in the luminous thin film, it can emit light at highefficiency. And, since no expensive apparatus is needed for themanufacturing, it costs at low.

[0028] And the luminous thin film of the solid state light-emissiveapparatus according to the present invention can be also manufactured bydissolving the crystal fine particles of nm size coated with insulatorand the fluorescent fine particles of nm size into common solvent, bysoaking a substrate into the solvent and then taking it out from thesolvent, whereby to make a mixed layer of the crystal fine particles ofnm size coated with insulator and the fluorescent fine particles of nmsize.

[0029] According to the above mentioned makeup, a mono layer whichconsists of the crystal fine particles coated with insulator and thefluorescent fine particles of nm size being densely and mutually alignedon the substrate, is obtained by one time processing of soaking asubstrate into the solvent and taking it out there-from, and the desiredthickness of the layer is obtained by repeating the above processing.

[0030] According to the above mentioned method, since those fineparticles can be densely packed with only a few gaps between those fineparticles in the luminous thin film, it can emit light at highefficiency. And, since no expensive apparatus is needed for themanufacturing, it costs at low. The afore mentioned crystal fineparticles of nm size coated with insulator preferably consists of asingle crystal fine particle of a semiconductor or a metal of nm sizecoated with insulator film of nm thickness.

[0031] Also, the single crystal fine particle of nm size is preferably aintrinsic or impurity-doped Si single crystal fine particle of nm size,and the insulator film is preferably a SiO₂ film of nm thickness.

[0032] Said fluorescent fine particle of nm size may be a semiconductorfine particle having a band gap energy corresponding to an energyranging from ultraviolet light to visible light. Also, a fluorescentfine particle of nm size may have a donor or/and an acceptor. Stillfurther, a fluorescent fine particle of nm size may be a semiconductorfine particle involving luminous atoms or luminous atom ions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will better be understood from thefollowing detailed description and the drawings attached hereto showingcertain illustrative forms of embodiment of the present invention; inthis connection, it should be noted that such forms of embodimentillustrated in the accompanying drawings hereof are intended in no wayto limit the present invention but to facilitate an explanation and anunderstanding thereof, in which drawings:

[0034]FIG. 1 is a diagrammatic cross-sectional view showing the makeupof a solid state light-emissive display apparatus of the presentinvention, wherein (a) is a drawing showing the makeup of double layerlamination of a layer composed of crystal fine particles coated withinsulator and a layer composed of fluorescent fine particles, (b) is adrawing showing the makeup of alternate lamination of each one layercomposed of crystal fine particles coated with insulator and composed offluorescent fine particles, and (c) is a drawing showing the makeup oflamination of a mixed layer composed of crystal fine particles coatedwith insulator and fluorescent fine particles;

[0035]FIG. 2 is a diagrammatic drawing for explanation of operatingprinciple of a solid state light-emissive display apparatus of thepresent invention, wherein (a) shows an enlarged view of crystal fineparticles coated with insulator, and (b) shows an enlarged view offluorescent fine particles;

[0036]FIG. 3 shows the makeup of a solid state light-emissive displayapparatus of the present invention by simple matrix driving, wherein (a)is a cross-sectional view, and (b) is a plane view;

[0037]FIG. 4 shows the makeup of a solid state light-emissive displayapparatus of the present invention by active driving, wherein (a) is across-sectional view, and (b) is a plane view;

[0038]FIG. 5 is a drawing for explanation of the method of manufactureof SiO₂-coated Si single crystal fine particles in accordance with thepresent invention; and

[0039]FIG. 6 is a drawing for explanation of the method of lamination ofcrystal fine particles coated with insulator and fluorescent fineparticles in accordance with the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

[0040] Hereinafter, a detailed explanation is given in respect toembodiment of the present invention, references being made to figures.In the drawing figures, it should be noted that the same referencecharacters are used to designate substantially the same or correspondingcomponents.

[0041]FIG. 1 is a diagrammatic cross-sectional view showing the makeupof a luminous part of a solid state light-emissive display apparatus ofthe present invention. FIG. 1(a) is a drawing showing the makeup ofdouble layer lamination of a layer composed of crystal fine particlescoated with insulator layer and a layer composed of fluorescent fineparticles layer, FIG. 1(b) is a drawing showing the makeup of alternatelamination of each one layer composed of crystal fine particles coatedwith insulator layer and of fluorescent fine particles, and FIG. 1(c) isa drawing showing the makeup of lamination of a mixed layer composed ofcrystal fine particles coated with insulator layer and fluorescent fineparticles.

[0042] In FIG. 1, a luminous part 1 consists of a lower electrode 2, aluminous thin film 3 laminated on the lower electrode 2, and atransparent upper electrode 4 formed on the luminous thin film 3. Saidluminous thin film 3 is, in case of FIG. 1(a), consisted of laminating alayer 6 composed of crystal fine particles coated with insulator and alayer 8 composed of fluorescent fine particles 7. Also in case of FIG.1(b), said luminous thin film 3 is consisted of alternately laminatingof a layer 6 composed of crystal fine particles coated with insulatorand a layer 8 composed of fluorescent fine particles 7. Further in caseof FIG. 1(c), said luminous thin film 3 is consisted of laminating amixed layer of crystal fine particles coated with insulators 5 andfluorescent fine particles 7. Said lower electrode 2 is, for example,n-type high conductive Si substrate 2, and said upper electrode 4 is ITOfilm which is conductive and transparent to visible light.

[0043]FIG. 2 is a diagrammatic drawing for explanation of operatingprinciple of a solid state light-emissive display apparatus of thepresent invention, wherein, FIG. 2(a) shows an enlarged view of layersof crystal fine particles coated with insulator, and FIG. 2(b) shows anenlarged view of layers of fluorescent fine particles.

[0044] In FIG. 2(a), said layers 6 are constituted as that crystal fineparticles coated with insulator 5 are mutually and densely aligned, andthis figure shows for an example where crystal fine particle coated withinsulators 5 is Si single crystal fine particle of nm size 5 a coatedwith SiO₂ film of nm thickness 5 b. Typically in size, the diameter ofSi single crystal fine particle 5 a is 7 nm, and the thickness of theSiO₂ film is 3 nm.

[0045] In FIG. 2(b), said layers 8 are constituted as that fluorescentfine particles 7 are mutually and densely aligned, and said fluorescentfine particle 7 is the semiconductor, for example ZnS, having the bandgap energy corresponding to the energy ranging from ultraviolet light tovisible light.

[0046] An explanation is next made in respect to luminescence mechanismof said luminous part.

[0047] Voltage is applied between the lower electrode 2 and the upperelectrode 4 so as to be positively high at the upper electrode 4. Thevoltage are distributed to respective insulators 5 b of crystal fineparticles coated with insulators 5 constituting the layer 6, that is,SiO₂ film 5 b of SiO₂ coated Si single crystal fine particles 5. Theelectrons 9 withdrawn from the lower electrode 2 is accelerated by theelectric field distributed to SiO₂ films 5 b, and pass through SiO₂films 5 b by tunneling or resonant tunneling transporting phenomenon,since the thickness of SiO₂ film 5 b is thin. Since the diameter of a Sisingle crystal fine particle 5 a is small, the electrons in Si singlecrystal fine particles 5 a passes without being scattered by phononsbecause of quantum size effect, that is, without loss of kinetic energy.As shown in FIG. 2(a), electrons 9 repeat acceleration in SiO₂ film 5 band lossless passing through Si single crystal fine particle 5 a atevery SiO₂ coated Si single crystal fine particles 5, whereby to obtaina kinetic energy sufficient to excite fluorescent fine particles 7 andto emit from layers 6 composed of SiO₂ coated Si single crystal fineparticles.

[0048] As shown in FIG. 2(b), the electrons 9 which have obtained thekinetic energy sufficient to excite fluorescent fine particles 7,collide with fluorescent fine particles of nm size 7, and by thecollision excitation create free electrons 11 and holes 12 in theconduction band and the valence band of fluorescent fine particles 7.Said electrons 11 and said holes 12 form free excitons 13 by coulombpotential based on the respective electric charges. Since theseelectrons 11 and holes 12 are enclosed inside the fluorescent fineparticle of nm size 7, that is, in the space of nm size, their coulombinteraction is strong, and the formation probability of free exciton 13increases, whereby the free exciton concentration increases. Since thefree exciton concentration is high, luminescence intensity generated byextinction of free excitons 13 increases. Since the free exciton energydepends on the band gap energy of the semiconductor crystal,luminescence wavelength can be chosen by choosing the kind ofsemiconductor. For example, blue color luminescence can be obtained byusing ZnS semiconductor, and red color luminescence can be obtained byusing GaAs semiconductor.

[0049] Thus, in accordance with the present invention, the generationefficiency of high energy electrons to excite fluorescent fine particlesis quite high, and the exciton concentration is also quite high,therefore, high efficiency and high brightness luminescence can beobtained.

[0050] Also, since electrons 9 are not scattered by phonons in theprocess of acceleration, dielectric breakdown of crystal fine particlecoated with insulators 5 does not tend to occur. Consequently, since itis possible to make the thickness of fluorescent thin film 3 extremelythin to raise the electric field intensity, a solid state light-emissivedisplay apparatus which is extremely thin type and has high reliabilitycan be obtained.

[0051] Also in case that a fluorescent fine particle 7 is doped with adonor or an acceptor, an exciton formed via a donor or an acceptor,namely a bound exciton 13 is formed. In case that a donor and anacceptor are doped, a bound exciton 13 is formed via a donor and anacceptor. In this case, too, since electrons 11 and holes 12 areenclosed inside fluorescent fine particles 7, that is, in the space ofnm size, their coulomb interaction is very strong, and the formationprobability of bound excitons 13 increases, whereby the bound excitonconcentration increases. Since the bound exciton concentration is highin this way, luminescence intensity generated by extinction of boundexcitons 13 increases. Also in this case, the luminescence wavelengthcorresponding to the depth of energy levels of a donor and an acceptorcan be obtained. For example, ZnS doped with Al as a donor and Cu as anacceptor provides green light luminescence. Also, by using asemiconductor including luminous atoms or luminous atom ions forfluorescent fine particles 7, the accelerated electrons 9 excite theluminous atoms or luminous atom ions by collision excitation, whereby togenerate fluorescence of specific wavelength when the luminous atoms orthe luminous atom ions transit from the excited state to the groundstate. For example, if Mn is included as luminous atoms in ZnSsemiconductor, yellowish orange luminescence can be obtained.

[0052] According to the present invention, since electrons 9 can beaccelerated at quite high efficiency, fluorescent fine particle layers 8having luminous center atoms can be made to emit light of highbrightness.

[0053] As described above, according to the present invention, electronscan be accelerated at quite high efficiency. Theoretically mentioned,since electrons can be accelerated without energy loss, it is possibleto obtain luminescence with an applied voltage corresponding to the bandgap energy of fluorescent fine particles. For example, if ZnSsemiconductor is used as semiconductor of fluorescent fine particles,luminescence is obtained with the applied voltage of about 4V, becausethe band gap energy of ZnS is about 3.7 eV. Consequently, luminescenceof high brightness is possible also by the makeup of FIG. 1(b) and (c).

[0054] An explanation is next given in respect to a solid statelight-emissive display apparatus of the present invention by simplematrix driving.

[0055]FIG. 3 shows the makeup of a solid state light-emissive displayapparatus of the present invention by simple matrix driving, whereinFIG. 3(a) is a cross-sectional view, and FIG. 3(b) is a plane view. Asolid state light-emissive display apparatus 30 comprises a substrate31, the plurality of the lower electrodes 2 in a form of mutuallyparallel stripes formed on said substrate 31, luminous thin film 3laminated on said substrate 31 with the lower electrode 2 formed on thesame, and the plurality of the upper electrodes 4 in a form of mutuallyparallel stripes formed on said luminous thin film 3 so to form aperpendicular matrix with said lower electrode 2. Said upper electrode 4is made of transparent ITO film.

[0056] By making the cross-sectional regions of the lower electrode 2and the upper electrode 4 as pixels, choosing an arbitrary one set fromthe plurality of the lower electrodes 2 and the plurality of the upperelectrodes 4, and by applying a voltage between the lower electrodes 2and the upper electrodes 4, the pixels at arbitrary positions are madeluminous.

[0057] In accordance with the above mentioned, images and mobile imagescan be displayed. Since the luminous thin film explained in FIG. 1 andFIG. 2 is used, a solid state light-emissive display apparatus 30 ofhigh efficiency and high brightness luminescence, thin type, and highreliability is provided.

[0058] An explanation is next given in respect to a solid statelight-emissive display apparatus of the present invention by activedriving.

[0059]FIG. 4 shows the makeup of a solid state light-emissive displayapparatus of the present invention by active driving, wherein FIG. 4(a)is a cross-sectional view, and FIG. 4(b) is a plane view. A solid statelight-emissive display apparatus 40 of the present invention comprisesthe plurality of the scanning wirings 41 in a form of mutually parallelstripes formed on a substrate 31, the first insulation layer 42laminated on the substrate 31 having said scanning wirings 41 formed onthe substrate, the plurality of the signal wirings 43 in a form ofmutually parallel stripes formed on said first insulation layer 42 so toform a perpendicular matrix with said scanning wiring 41, the secondinsulation layer 44 laminated on said first insulation layer 42 havingsaid signal wirings 43 formed on the first insulation layer 42, thepixel electrodes 45 formed on said second insulation layer 44 and in theproximity of matrix cross sectional region, the luminous thin film 3laminated on said second insulation layer 44 having pixel electrodes 45formed on the second insulation layer 44, and the transparent upperelectrode 4 covering the whole display surface formed on said luminousthin film 3.

[0060] Near matrix cross sectional region and on said scanning wiring 41is set a gate electrode 46 of a thin film transistor protruding into thefirst insulation layer 42, a channel semiconductor layer 47 of a thinfilm transistor is set opposing to said gate electrode 46 on the firstinsulation layer 42, one end of said channel 47 is connected to thesignal wiring 43 via a drain electrode 48, and the other end of saidchannel 47 is connected to the pixel electrode 45 via a source electrode49.

[0061] In accordance with the above mentioned, images and mobile imagescan be displayed. As a luminous thin film explained in FIGS. 1 and 2 isused in the present invention, a solid state light-emissive displayapparatus of highly efficient and bright luminescence, thin type, and ofhigh reliability can be provided. Also according to the present makeup,since the voltage ratio between a pixel electrode switched on by a thinfilm transistor and a pixel electrode switched off by a thin filmtransistor is large, the extinction ratio between pixels becomes high,and so high resolution display is made possible. High speed display isalso possible because it can be driven with smaller power than by simplematrix system.

[0062] Explanation is next given in respect to the method of manufactureof a solid state light-emissive display apparatus of the presentinvention.

[0063] The method of manufacture is first explained in respect to themaking of the single crystal fine particles coated with insulatorconsisting of Si single crystal fine particles coated with SiO₂ film.

[0064]FIG. 5 is a drawing for explanation of the method of manufacturingof SiO₂-coated Si single crystal fine particles in accordance with thepresent invention. In this figure, the manufacturing apparatus 50 hasopen tube which consists of a part 51 for producing Si single crystalfine particles and a part 52 for coating single crystal fine particleswith SiO₂ film, wherein SiH₄ (silane) gas 54 is made to flow into thetube from the inlet 53, SiH₄ gas 54 is pyrolized to form said Si singlecrystal fine particles 5 a of nm size at the part 51 which is held atthe pyrolysis temperature of SiH₄ 54, and Si single crystal fineparticles produced are floating in the atmosphere. Si single crystalfine particles 5 a thus produced are transferred into said part 52 bythe gas flow, that is, by flowing gas, or by gravity, and SiO₂ film 5 bof nm thickness is formed on the surface of Si single crystal fineparticles 5 a in the state of floating in the atmosphere by oxygen 55introduced into a part 52. The SiO₂-coated Si single crystal fineparticles 5 thus formed are transferred to the outlet 56 by flowing gasor by gravity and collected.

[0065] By the method mentioned above, it is possible to produceSiO₂-coated Si single crystal fine particles mutually separated withoutforming porous aggregate formed by mutual contact of said single crystalfine particles.

[0066] Explanation is next made in respect to the formation of luminousthin film by laminating of single crystal fine particles coated withinsulator and fluorescent fine particles on a substrate.

[0067]FIG. 6 is a drawing for explanation of the method of laminating ofsingle crystal fine particles coated with insulator and fluorescent fineparticles in accordance with the present invention.

[0068] The figure shows soaking the substrate 62 into the solvent 61such as water and pulling up said substrate, wherein said substrate62has the lower electrodes 2 or the pixel electrodes 45 formed on it andin said solvent 61 single crystal fine particles coated with insulator 5or fluorescent fine particles 7 are dissolved. The fine particles 63which are single crystal fine particles coated with insulator 5 orfluorescent fine particles 7 in the solvent 61 are adhered to thesubstrate surface 62 so as to minimize the surface free energies such asthe surface tension energy of the solvent 61, and the adsorption energyof fine particles 63 to the substrate 62, as the result, a mono layer 64consisting of the fine particles 63 aligned mutually and densely on thesubstrate 62 is formed.

[0069] By the repeating of soaking and pulling up of the substrate 62,the fine particle layers 64 can be mutually and densely laminated todesired thickness corresponding to the repeating number.

[0070] In order to form the luminous thin film 3 of the makeup shown inFIG. 1(a), single crystal fine particles coated with insulator 5 andfluorescent fine particles 7 are dissolved individually in differentsolvents, and the above mentioned repeating process is repeated with onesolvent to laminate to the desired thickness, followed by the repeatingprocess with the other solvent to laminate to the desired thickness.

[0071] In order to form the luminous thin film 3 of the makeup shown inFIG. 1(b), single crystal fine particles coated with insulator 5 andfluorescent fine particles 7 are dissolved individually in differentsolvents, and the above mentioned repeating process is alternatelyrepeated with each solvent to laminate the layer 6 of single crystalfine particles coated with insulator and the layer 8 of fluorescent fineparticles alternately one by one.

[0072] In order to form the luminous thin film 3 of the makeup shown inFIG. 1(c), single crystal fine particles coated with insulator 5 andfluorescent fine particles 7 are dissolved in a common solvent, theabove mentioned repeating process is repeated with the common solvent tolaminate the mixed layer of crystal fine particles coated with insulator5 and fluorescent fine particles 7 to the desired thickness.

[0073] Since fine particles are aligned densely with few gaps in theluminous thin film thus formed, the electric field distribution isuniform, tunneling probability increases, and electrons can beaccelerated at high efficiency. Also, brightness is high becausefluorescent fine particles are densely aligned.

INDUSTRIAL APPLICABILITY

[0074] As will have been appreciated from the foregoing description, thepresent invention provides a solid state light-emissive displayapparatus of dramatically higher brightness and efficiency, higherreliability, and of thinner type than existing display apparatuses. Alsoin accordance with the present invention, this solid statelight-emissive display apparatus can be manufactured at low cost. Thus,if the apparatus of the present invention is used as the displayapparatus of mobile phones or others, it is quite useful because of muchlower power consumption, higher brightness, thinner type, and higherreliability than existing liquid crystal displays.

1. A solid state light-emissive display apparatus, characterized in thatit comprises: a luminous part comprising a luminous thin film composedof laminated or mixed of crystal fine particles coated with insulator ofnm (nanometer) size and fluorescent fine particles of nm size; and alower electrode and a transparent upper electrode sandwiching saidluminous thin film, whereby to obtain luminous display by impressingalternating voltage or direct current voltage between said upper andlower electrodes.
 2. A solid state light-emissive display apparatus asset forth in claim 1, characterized in that: said crystal fine particlescoated with insulator of nm size consist of single crystal fine particleof nm size of either a semiconductor or a metal, and an insulator filmof nm thickness coating the surface of said single crystal fineparticle.
 3. A solid state light-emissive display apparatus as set forthin claim 2, characterized in that: said single crystal fine particles ofnm size are either intrinsic Si single crystal fine particles of nm sizeor those doped with impurities, and said insulator film is SiO₂ film ofnm thickness coating the surface of said Si single crystal fineparticles.
 4. A solid state light-emissive display apparatus as setforth in claim 1, characterized in that: said fluorescent fine particlesof nm size are the semiconductor fine particles having a band gap energycorresponding to an energy ranging from ultraviolet light to visiblelight.
 5. A solid state light-emissive display apparatus as set forth inclaim 4, characterized in that: said fluorescent fine particles of nmsize have either a donor or/and an acceptor.
 6. A solid statelight-emissive display apparatus as set forth in claims 4 or 5,characterized in that: said fluorescent fine particles of nm size arethe semiconductor fine particles involved with either a luminous atomsor a luminous atom ions.
 7. A solid state light-emissive displayapparatus as set forth in claim 1, characterized in that: said upper andlower electrodes are formed in a form of matrix configuration, andintersection regions of said upper and lower electrodes are used aspixels which are driven by simple matrix driven operation.
 8. A solidstate light-emissive display apparatus as set forth in claim 1,characterized in that: scanning wirings and signal wirings are formed ina form of matrix, a thin film transistor is set at an intersectionregion of said scanning wiring and said signal wiring, a gate electrodeof said thin film transistor is connected to said scanning wiring, adrain electrode of said thin film transistor is connected to said signalwiring, a source electrode of said thin film transistor is connected toa pixel electrode, said luminous thin film is sandwiched by said pixelelectrode and said upper electrode, whereby each said pixels areactively driven by said thin film transistors by choosing said scanningwiring and signal wiring.
 9. A method of manufacturing of a solid statelight-emissive apparatus, characterized in that it comprises steps:producing Si single crystal fine particles of nm size by pyrolyzing SiH₄in a floating state of said Si single crystal fine particles inatmosphere; transferring said Si single crystal fine particles in thestate of floating into O₂ gas atmosphere; and coating the surface ofsaid Si single crystal fine particles with SiO₂ film of nm thickness.10. A method of manufacturing of a solid state light-emissive apparatus,characterized in that it comprises steps: dissolving crystal fineparticles coated with insulator of nm size and fluorescent fineparticles of nm size into respective solvents; and soaking a substrateinto each solvents and pulling it up, whereby laminating of a singlecrystal fine particle layer and a fluorescent fine particle layer.
 11. Amethod of manufacturing of a solid state light-emissive apparatus,characterized in that it comprises steps: dissolving crystal fineparticle coated with insulator of nm size and fluorescent fine particlesof m size into common solvent; and soaking a substrate into said solventand pulling it up, whereby laminating a mixed layer composed of singlecrystal fine particles coated with insulator and fluorescent fineparticles.
 12. A method of manufacturing of a solid state light-emissiveapparatus as set forth in claim 10 or 11, characterized in that: saidcrystal fine particle coated with insulator of nm size consists of asingle crystal fine particle of nm size of either a semiconductor or ametal, and a insulator film of nm thickness coating the surface of saidsingle crystal fine particle.
 13. A method of manufacturing of a solidstate light-emissive apparatus as set forth in claim 12, characterizedin that: said single crystal fine particle of nm size is eitherintrinsic Si single crystal fine particle of nm size or that doped withimpurity, and said insulator film is SiO₂ film of nm thickness coatingthe surface of said Si single crystal fine particle.
 14. A method ofmanufacturing of a solid state light-emissive apparatus as set forth inclaim 10 or 11, characterized in that: said fluorescent fine particle ofnm size is a semiconductor fine particle having a band gap energycorresponding to an energy ranging from ultraviolet light to visiblelight.
 15. A method of manufacturing of a solid state light-emissiveapparatus as set forth in claim 10 or 11, characterized in that: saidfluorescent fine particle of m size has a donor or/and an acceptor. 16.A method of manufacturing of a solid state light-emissive apparatus asset forth in claim 14, characterized in that: said fluorescent fineparticle of nm size is a semiconductor fine particle involving aluminous atoms or a luminous atom ions.